The present invention relates to a process for spectral sensitization of a silver halide emulsion and to photographic materials produced therewith.
For spectral sensitization of silver halide emulsions, the sensitizing dye is in general adsorbed on the surface of the silver halide crystals after the chemical sensitization. However, it is also usual to carry out the spectral sensitization simultaneously with or before the chemical sensitization. Thus, a process is described in U.S. Pat. No. 4,225,666, in which a part of the sensitizing dye is added during, and the remainder is added after the formation of the silver halide crystals. From EU-A-0,069,596, it is known to add a part of the sensitizing dye during the chemical sensitization and a second part of the sensitizing dye or a corresponding quality of another dye after the chemical sensitization.